The code for that part is really simple and works fine for me and my testers, just checked it myself again. My best guess is that your file got damaged. I'll look into it more, but I'm 90% sure the problem is on your end - try redownloading the game and let me know if it fixes the issue.
No worries, your progress won't be lost - you can easily import your all your data from the old game's save folder. It's as simple as copy-pasting the files, but feel free to ask if you need any help ^^